FERRARIST
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| posted on 14/12/14 at 10:31 AM |
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Brake proportioning valve issue
Never using brake valve before, and i guess there is problem with it.
Have 2 valves for front and rear brakes - rear is bargain wilwood from ebay, front is cheapy from same place.
Wilwood brake pedal box with balance bar.......problem is that when i bleed the front calipers and pump brake pedal few times fluid pressure still
remains into the front brake circuit and unless i open the bleed knop in one of the calipers, i can't move a tyre......
There was no In or Out direction on the valve, i tried opposite direction of fluid - no brake pressure - so i guessed that it was right fitted from
the beginning.
So when pedal pressed, fluid did not returns and hold brakes on until i open caliper and bleed some fluid.
Did i mess something or the valve is rubbish?
Below is picture of my front brake line setup, please don't ask why i change the place of brake and clutch pedals..
 
Description
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CosKev3
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| posted on 14/12/14 at 11:10 AM |
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Why have you fitted a valve to front brakes?
I always understood it that the pressure to rear brakes needs one to reduce the pressure to stop the rear brakes locking up before the fronts on a set
up without balance bar, but you've got a balance bar so shouldn't need a valve in rear brake line either?
Ref the brakes sticking on, are you sure the pedal/master cylinder is returning fully off after you release the pedal?
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FERRARIST
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| posted on 14/12/14 at 11:38 AM |
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quote:
Originally posted by CosKev3
Why have you fitted a valve to front brakes?
I'll run 250/64/18 wide slicks in front, it's my first locost build, there is no smooth surface tracks here and at least in the beginning
i need to experiment.......i'm ex go-karting driver and always use left foot braking......i might remove it, but not for now......
quote:
Originally posted by CosKev3
Ref the brakes sticking on, are you sure the pedal/master cylinder is returning fully off after you release the pedal?
Yes, both master cylinders returns fully.....
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Andy S
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| posted on 14/12/14 at 11:52 AM |
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It appears that you have a bias pedal dual master cylinder set up - there should be no need for a proportioning valve - the bias is adjusted at the
balance bar on the pedals on the principle of mechanical leverage and the added ability to change the diameters of the M/C's.
Proportioning valves are generally used when there is no possibility of making a mechanical adjustment to the force to a single (single or dual
circuit) M/C .
You have a mixture of systems - best to remove the valves and then sort out the bias systems correctly.
[Edited on 14/12/14 by Andy S]
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designer
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| posted on 14/12/14 at 12:15 PM |
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Have to agree with the posts.
You only need a valve on the rear, and a dual circuit system needs no valves at all.
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theprisioner
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| posted on 14/12/14 at 12:33 PM |
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Seals could be round wrong way in master cylinder that would then hold pressure?
http://sylvabuild.blogspot.com/
http://austin7special.blogspot.co.uk/
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minitici
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| posted on 14/12/14 at 12:59 PM |
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As posted above, if the brake pedal has and adjustable bias mechanism use that to set the balance.
If there is no bias adjustment, fit the proportioning valve in the rear circuit only.
[Edited on 14/12/14 by minitici]
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FERRARIST
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| posted on 14/12/14 at 02:17 PM |
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Well, with so many opinions towards removing the valve, maybe it will be pointless to use valve in front......and less hassle for me too.....hope that
balance bar will be enough for the job....
Thanks.
[Edited on 14/12/14 by FERRARIST]
[Edited on 14/12/14 by FERRARIST]
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Doctor Derek Doctors
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| posted on 14/12/14 at 07:45 PM |
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You have a bias bar, that is perfectly adequate. Get rid of both pro portioning valves as they are completely unnecessary and by the sounds of it just
causing problems.
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